Reproduction of confused flour beetle Tribolium confusum Du Val (Coleoptera: Tenebrionidae) on common and spelt wheat and their products

Abstract

The interest in spelt wheat production has grown in recent years but there is hardly any information on pest development on that wheat species in storehouses. The influence of common and spelt wheat and their products on the reproduction and offspring of confused flour beetles Tribolium confusum Du Val was studied under laboratory conditions (22-25 °C and 40-60% RH). The experiment was carried out in four replications with four, 10 and 20 insects over a period of six months. The reproduction of confused flour beetles significantly varied depending on the wheat species and product. The highest reproduction rate was recorded on spelt wheat (Triticum spelta L.). The greatest number of offspring beetles appeared on spelt wheat flour (23469). The number of offspring beetles was higher on common (7044) than on spelt wheat kernels (5469). No offspring developed on common wheat pasta while only 4 young beetles were found on spelt wheat pasta. Offspring numbers increased with storage period up to a point but further on they depended on insect number. The number of insects increased over the first four months but decreased later on and the mortality rate was higher. Initial population density affected the offspring numbers but offspring numbers did not rise proportionally with the rising initial population density. Considering the species of wheat, higher mortality was recorded in common wheat. Regarding the type of product, the highest mortality was recorded in pasta, then in kernels and the lowest in flour. The paper shows that confused flour beetles develop extremely well on spelt wheat, even better than on common wheat which is widely grown in Serbia.

Poslednjih godina povećan je interes za proizvodnju pšenice spelte. Malo je informacija o mogućnosti razvića štetočina u skladištima na ovoj vrsti pšenice. Ispitivan je uticaj vrste pšenice i njenih prerađevina na reprodukciju i formiranje potomstva malog brašnara Tribolium confusum Du Val u laboratorijskim uslovima (22-25 °C i 40-60% RVV). Ogled je postavljen u četiri ponavljanja sa po četiri, 10 i 20 insekata i praćen šest meseci. Razmnožavanje malog brašnara se značajno razlikovalo u zavisnosti od vrste pšenice. Najveća reprodukcija zabeležena je na spelti (Triticum spelta L.). Najveći broj potomaka se razvio na brašnu od spelte (23469). Na zrnu pšenice dobijen je veći broj potomaka (7044) od broja potomaka na zrnu spelte (5469). Na testeninama od pšenice nije dobijeno potomstvo, dok je na testeninama od spelte dobijeno samo 4 potomka. Dužina čuvanja utiče na povećanje brojnosti potomstva pozitivno, do određene granice, a dalje zavisi od brojnosti insekata i količine dostupne hrane. Do četiri meseca brojnost insekata se povećavala, a kasnije opadala i povećavala se smrtnost. Osim vrste hrane i početna gustina populacije utiče na brojnost potomstva, ali se brojnost potomstva ne povećava srazmerno povećanju početne gustine populacije. U zavisnosti od vrste pšenice najveća smrtnost zabeležena je na običnoj pšenici. U odnosu na vrstu proizvoda najveća smrtnost bila je na testeninama, zatim na zrnu, a najmanja na brašnu. Ovaj rad ukazuje da se mali brašnar odlično razvija na spelti i svim proizvodima od spelte, čak bolje nego na mekoj pšenici koja se gaji u našoj zemlji.